I've discribed in detail our strategy for 10man normal in this threat: http://www.tankspot.com/showthread.php?74173-Magmaw-adds-as-Warrior&p=492253#post492253 (should link post #7 but is not working for me).
We had a comparable problem that our dps could not burn the parasites down fast enough when we first tried to do so. Since you are a prot warrior maybe our strategy is something for you. It simplifys it for everybody but the warrior tank who has to be quite alert. But if you think that you can do it, try it out.